When freezing weather threatens a solar water heating system, one means of protecting the system is to drain the water from the solar panel and all conduits which could be affected by the freezing weather. After the freezing weather has left, the system can be refilled for subsequent use. Another means is to circulate the stored hot water during freezing weather which prevents freezing, but also cools the stored water; and in the event of excessive cold weather, it might be necessary to heat the water by some other means to prevent it from freezing as the stored water drops to a low temperature.
Another means used in solar water heating systems where freezing temperatures are encountered is the use of a heat exchanger means where an antifreeze solution may be added to the water used as the heat collection fluid which is subjected to the freezing temperatures.